Heretofore the use of pulse oximeter finger probes has been limited to the use of a costly reusable probe, which is available in only one size, and is contaminated by use on a patient, or cheaper, single-use probes, which, in the aggregate, amount to a considerable expenditure for a health care institution. The present invention relates to a method of making and affixing a reusable finger probe to a patient by means of a finger clip apparatus with a disposable liner insert so that there is no contact between the costly, reusable portion of the probe and the patient. The contaminated liner, which is relatively inexpensive, can then be discarded after single patient use and the probe and finger clip can be re-used with a new liner. Additionally, such disposable inserts may be provided of different sizes and would greatly enhance the fit and function of the finger clip on the patient. This is important for several reasons. Firstly, a fitted finger clip would be much more comfortable to wear than conventional finger clips. Secondly, a fitted finger clip would allow the transmission and reception of infrared light from the LEDs of the probe without interference from extraneous light sources around the front and edges of the finger, and thirdly, a fitted finger clip would evenly distribute the pressure from the spring of the finger clip and would be much less likely to restrict blood flow to the digit and thereby cause erroneous oxygen saturation readings.